1. Field of the Invention
Bone harvesting is performed in medicine both for the diagnosis of various diseases as bone biopsies as well as to obtain mainly cancellous bone for auto-transplantation for therapeutic purposes.
2. Description of the Related Art
Besides direct surgical harvest following operative exposure of bone, four different percutaneous methods are currently used to harvest bone:
1) By insertion of a relatively thin, slightly conical needle into the bone which might harvest a small amount of bone upon retraction of the instrument. This method has the disadvantage that only small amounts of bone can be harvested, and that the histological architecture of the bone can be disturbed substantially.
2) By using a cylinder osteotome with a round interior which can be inserted into the bone using rotation or oscillation. Thus a bone core is created which might be retracted with the osteotome as described in G8806721.1. This method has the advantage that excellent bone material can be removed in significant quantities. The disadvantage of this method exists that the bone core tends to stick on its base and thus often can be removed only with substantial difficulties. For this reason the bone harvest has to be made rather deep until soft tissue behind the bone is reached. Another option is the attempt to loosen the bone core by angling and levering the osteotome, which may result in substantial tissue trauma and which nevertheless may not be able to detach the bone core adequately for its removal.
3) By the use of an osteotome which is inserted with a mallet and which consists of a hollow cylinder with an internal ridge. After inserting this osteotome the resulting bone core can be sheared off, due to the existing longitudinal ridge and subsequently be removed easily. The disadvantage of this method is, that a substantial amount of force is necessary to have this osteotome inserted into the bone. Without general anesthesia such a procedure is usually not possible. Additionally the high energy necessary for insertion of these osteotomes, which is usually done with a mallet, may be the cause of substantial soft tissue trauma.
4) Using an osteotome which has one or several teeth reaching into the inner surface of a cylinder as described in International Patent W096/27333 and which may be inserted either using a mallet or by rotation. If this osteotome is inserted with a mallet, the aforementioned disadvantages cannot be avoided. Conversely a substantial amount of bone material is lost, if this osteotome is inserted by rotation. On the other hand, if this osteotome is inserted with too little progression (.about.less than twice the thickness of the tooth) no adequate retention of the bone core is the result, thus not allowing a removal of the bone core without substantial manipulation and above mentioned disadvantages.
The purpose of this invention is to develop a bone harvesting device thus that bone can be obtained in substantial quantities easily, reliably and without substantial destruction of the bone structure.